Perforating unit



Aug 7, 195e P. H. TAYLOR 2,757,735

PERFORATING UNIT YFiled March 31, 1953 3 sheets-sheet 1 75 3 s2 .90 g4 22 70 '27 y 77 3 SheetsSheet 2 INVENTOR. qj/Zor F. H. TAYLOR PERFORATING UNIT Aug. 7, 1956 Filed March 31, 1953 Aug. 7, 1956 P. H. TAYLOR PERFORATING UNIT 5 Sheets-Sheet 3 Filed March 3l, 1953- United States Patent-O 2,757,735 PERFORMING UNIT Paul H. Taylor, Grand Island, N. Y., assignor to Wales- Strippit Corporation, North Tonawanda, N. Y., a corporation of New i erk Application March 31, 1953, Serial No. 345,957

21 Claims. (Cl. 164-94) The present invention relates to self-contained perforating implements for punching holes in sheet metal and similar material, and more particularly to a selfcontained perforating unit which is of the general type shown in the U. S. Patent to Wales No. 1,955,866, granted April 24, 1934, and which is intended for use in a conventional press having a lower supporting bed and an upper ram which is movable vertically toward and from the bed.

Self-contained perforating implements of the type shown in Patent No. 1,955,866 have found wide use in industry because of the rapidity with which they can be set up and because of their flexibility for use in perforat- A ing short and medium production runs of metal sheets. In the self-contained perforating units of the character disclosed in Patent No. 1,955,866, there is required, aside from the punch itself, a stripper member, a stripping spring for cooperating with the stripper member to strip the punch from the work after the work has been perforated, and means for returning the punch and the stripper member to initial position to provide clearance for insertion of another workpiece between the punch and the die. have been conventionally used for stripping the punch from light workpieces of the order of one-eighth inch to one-quarter inch thickness. These heavy duty springs, however, have been extremely critical in design in that each such spring is suitable for use only within a limited range of operation, and each such spring accordingly has had to be designed for a particular thickness of workpiece which is to be stripped. Because of this it has heretofore been necessary to purchase one series of perforating implements for perforating stock up to oneeighth inch in thickness and another series of implements for perforating stock from one-eighth inch to one-quarter inch thickness of stock. When stock of both one-eighth inch and one-quarter inch thickness was to be perforated,

the heavier equipment was purchased and used for both:

purposes, thereby reducing the capital expenditures for equipment.

Heretofore, furthermore, there have been no perforating implements of the self-contained nature which would perforate from the thinnest stock up to heavier stocks such as stock three-quarter inch in thickness. While the amount of work to be done in the one-half inch to threequarter inch range is not great, there is a considerable quantity of perforating to be done in a range up to onehalf inch thickness. Heretofore, however, it has not been practical to perforate this heavier stock up to onehalf inch thickness because the stripping problems involved in withdrawing the punch from the work were such that it was impossible to design a mechanical spring which would effect stripping of more than one stock Heretofore heavy duty metal coil springs.

thickness. Thus for about each one-eighth inch range in 2,757,735 Patented Aug. 7, 1956 This cannot be accomplished with mechanical springssince when such a spring is designed for a given condition it only works satisfactory at the stroke and with the force for which it was designed.

In addition to all this, mechanical springs have definite limitations as to life.

Another difficulty in making conventional perforating units universal in use is that with standard mechanical spring stripping applications, because of the single purpose nature of the stripping spring, it is necessary for diterent perforating conditions to remove the spring from the perforating unit and to replace it with a heavier or a lighter spring to suit the condition encountered. Coupled with the fact that it is ordinary practice to overload mechanical springs it will be obvious that for punching a range of from one-eighth inch to three-quarter inch thickness and for punching various hole diameters and shapes, it would be necessary to have a multitude of removable stripping springs.

Still another difficulty with mechanical springs is that if the heaviest mechanical spring is used in the lightest possible application, the forces required for actuating a plurality of perforating units might well stall the press in which the units are to be used. Therefore, in addition to the necessity for having suicient pressure for a heavier job, there is also the necessity for being able to relieve the pressure for a lighter job where a multiplicity of perforating units are to be used. If the stripping force is in excess of requirements, it merely absorbs energy from the press, preventing maximum performance of the press for a given stripping requirement.

For the foregoing reasons these self-contained perforating units have been limited in use to those applications where the equipment could be justified by virtue of the fact that the run was sufficiently long so that the customer could amortize the purchase price of the equipment over the length of the run.

In an eort to overcome the deiiciencies and drawbacks of self-contained perforating implements using mechanical springs, I have devised perforating implements using liquid springs for stripping, as disclosed, for instance, in my pending U. S. patent application Serial No. 185,604, filed September 19, 1950, now Patent No. 2,732,898, granted January 31, 1956. However, while the use of a liquid spring in itself has remarkable advantages with respect to the ability to punch holes of larger diameter and through stock of greater thickness with a given holder width, and while perforating units employing liquid stripping springs are excellently suited for certain purposes, such units as heretofore constructed do not possess the universality and adaptability for perforating from zero to three-quarter inch thickness stock while maintaining the narrow holder widths that are required in order to be able to punch simultaneously a plurality of holes on close hole centers.

There is another problem involved in trying to achieve a universal self-contained perforating implement; that is in regard to other than circular holes. This problem arises from the fact that because of its shape the hole, which is to be punched, may be so disposed with reference to the axis of the punch that the stripping force required is greater on one side of that axis than on the 3 other. This, of course, requires a stripping spring tailored to that requirement. A coil spring designed and mounted for punching a circular hole cannotlproperly effect stripping in 'such a case `'unless it i's changed in posiytion to s'uit the non-circular shape of hole which is 'to be punched.

In addition tothe above requirements, in order to achieve universality, the punching member of the unit itself must be sb adapted that it can readily be ferner/ed from the unit so that for perforating material of great thickness a punching member can be employed having a large body, while forlp'erforating a small hole in light gauge material a punching member 'of reduced diameter but capable of replacing the large-bodied punching member vcan b'e used. Y Moreover the punching members must be so vdesigned that when 4th'e punching member of reduced diameter is used there will be no transition pointv between the operative end of the punch andthe body of the punch, where stresses will be set up in heat-treating that would cause breakdown of the punch in use.

()ne object of the present invention isto provide a self-contained perforating implement, which will be universal in character and which will perforate from zero to three-quarter inch thickness stock with the maximum hole size equal to the maximum stripping value of the spring. To this end it is a further purpose of the invention to provide llexibility and 'in'terchangeability, 'of punches, dies, and stripping pressures, so that the perforating implement will be completely-flexible with respect to shapes and sizes of holes and gauges of material which it can perforate within its 'capacity range. g

Another object of the invention is to provide a selfcontained perforating implement which has `strippingtlex b'ility such that it can be used not only to perforate circular holes, but to 'perforate odd and asymmetrical shapes even in heavy gauge material.

Another object of the invention is to provide a selfcont'ained perforating implement in which the stripping force can be 'adjusted to accommodate an eccentric or asymmetrical stripping condition and to 'equalie the stripping loads at opposite sides of th'e airis f 'the punch regardless of zthe shap'e'o'fthe hole which'is vto 'be punched.

Another obect 'of the invention 'is to provide 'fa selfcontained perforating irriplem'ent in which the stripping load o'r force can 'be adjusted while 'the Yifnrplei'nnt itself is in :the press.

Another object of the invention 'is to provide v'a `'self- 'ontained perfrating implement in which the strokes 'ef the punch and of the stripping apparatus 'can-be kept constant despite reduction in length lof the 'punch as v'the punch is ground back in sharpening.

Another object of the invention l'is to'provide a 'selfcontained perforating implement in which low cost replaceable punches maybe used, and in which leach punch uses but a small portion of critical alloy steel.

Another object of the invention is to provide a selfcontained perforating implement of the character 'described in which a headless punch can be employed.

Another object of the invention is to provide a selfcontained perforating unit in which either a headless or a headed punch can be used.

Another object of the invention is -to provide a selfcontained perforating implement employing -insert punches for perforating holes'of small diameter in lighter gauge materials.

Another object of the invention is to provide *a `selfcontained perforating implement in'whichth'e punchbody is guided directly in the C-frame, Vthereby increasing vthe accuracy of the implement. Heretofore the punch has been mounted in the strippingmember which l"in turn has been mounted in the holder'or C-frame 'which'has meant that there was one manufacturing tolerance allowed between the stripping member and theframeand another manufacturing tolerance allowed :between 'fue 4 punch and the stripping member, and there was always the possibility of build-up of the two tolerances.

Another object of the invention is to provide a selfcontained punch in which the stripping means has a floating mounting so that the stripping forces are not carried through the perforating arm to the punch, but the punch is guided directlyby the C-frame.

Still another object of the invention is to provide a selfcontained perforating implement in which the shut-height of the implement can be held to a minimum While providing the maximum grind life on the punch.

Another object of theinvention is to provide a selfcontained p'efor'a'ting implement having 'a relatively large stripping pressure area adapted to prevent distortion from punching of a thick perforated workpiece.

Another object of the invention is to provide a selfcontained perforating implement in which the stripping pressure lplate can be changed and in which plates can be employed `to compensate for tapered or other shapes o'ffstruct'ral steel which are to be perforated.

Other objects of the invention will be apparent hereinafter from the specification and from 'the recital of the appended claims.

ln the drawings:

Fig'. l is a side elevation, with parts broken away, showing a self-contained perforating implement constructed according to one embodiment of this invention;

Fi'g. 2 is a plan view of this implement with one of the punch-retainer 'plates removed;

Fig. 3 is a fra'g'r'nei-itary section taken on the line -33 df Fig. l, looking in the direction lof the arrows, and Vshowing one shape of removable die plate that rnay be 'used inthe implement;

Fig. 21 i's a section o'n the line 4-'4 of Fig. 1 but on a lai-'ger s'c'ale and looking Iin the direction of the arrows;

Fig. 5 is la sec-tion on the -lin'e 5--5 of Fig. 4, looking in the direction of the arrows, la'nd showing 'particularly details of fthe lifter springs for lifting the perforating punch `stripper assembly and returning it to -initial position;

Fig. '6 'is a view lof the perforating implement, lsi'mla'r to Fig. 1,6111 shwing-a smaller size, insert-type punch mounted therein;

Fig 7 is la fragmentary aiiialfs'e'ctin 'showing particu- {arly 'another 4foi-1n 'of insert 'punch 'that 'fina'y be used in 'the implement; and Fig. v8 is afseetionsimilar'to'lig. 7 but showing 'a's'till fur'th'er form o'f insert t'p'i'r'n'ch that may vbe used "in 'the implement.

Referring now -to the `drawings iby numerals 'of refe'rence and liir'st Ito the larribodirnent -o'f the nnven'ti'cmshown i'n Figs, l 'to '5 inclus'iv'e, `10 'denotes a C-frame -or holder vhaving upper 'and lo'wer a'rms 11 and y12, respectively.

Thepper 4Aa'rm l1-'of the C-frame has a bore 15 i'n whichthe'punch I6-is mounted to reciprocate. The punch is secured -atvits upper end to a 'punch cap member -or plate 18 by means of a screw 20 having its head countersunk 'iiito vx'the pla'te 18. The Iscrew l0 is 'held I'against -rotation'with 'respect 'to `-the -punch f6 by a set-screw 21 that'th'rea'dsinto'theipunch. One or more 'washers '22 may be interposed lbetween the upper -faee of lthe punch '16 and lthe `under 'fa'ce 'of 'the -plate I8 to properly 'position 'the operating end -jf vthe 'punchin accordance with-the vsharpened"height-of the punch, as will be described :fur- 'thervhereinaften lMounted torecipro'ctein holes 2'5 and-26 provided in 'the' upper 4'a'rm A-Jfl ofthe i`{Tf-frame. at opposite `sides^of th'e bore "15'forthe 'punch are 'tv'v'o liquid'springs 27 and 28. I'he'senrayfbe'ofistandard'construction, and are preferably of 'thetype'disclds'ed'in`the`pending U. `S. patent application of George "Wlesandthe presentinventon'Serial No. 228,245, :filed May 25, '1951, 'now Patent No. 2,729,440,`issued January v3, 19:56.

The'`t`wo"s'p"rings 27 a'n`cl"2"8 are'id'entical'in construction, b'uftne Ifthand sprint-"27 is'shown in section in Pig. '1.

ach spring cmp'n'ses a container 30 which istilled with a compressible liquid, such as silicone oil, and which is formed centrally with a cylinder 31 in which a pisto'n 32 reciprocates. ,A seal 33 is carried bythe piston to prevent leakage of liquid from the container as the piston reciprocatesin the cylinder.A The pistonshasa rod or stem portion 34 projecting outwardly'oflthe container through a seal 35. vThis seal is heldfin. position by ,the nutV or cap rnember 36 that threads-onto the cylinder y31.,` The piston rods 34 of the two springs are adapted to seat at their upper ends 'in recesses 38 formed in the plate 18. The under face of the plate is formed with two countersunk clearance recesses 39 adapted to receive the nuts 36 when the plate 18 is depressed on the working stroke of the punch 16, as shown in Fig. 5.

Each of the liquidsprings 27 and 28 is provided with a threaded extension 40 at its lower end which is yexternally threaded to thread into a stripping pressure plate 42. A piston 44 is mountedo be adjustablein the threaded extension 4t) of each spring to act asa force adjuster to adjust the force of the spring. Adjustment of each piston 44 is effected by a screw 45 which threads into an internally threaded bore portion of the corresponding extension 40. The stripping plate 42 has a hole 57 therethrough in alignment with the hole 15 of the upper arm 11 of the C-frame so as to permit the operating end 48 of the'punch member 16 to project therethrough for the perforating operations.

The liquid springs 27 and 2S are inserted in the holes 25 and 26 in the C-frame, but these holes 'simply afford clearance for the reciprocalmovement of these' springs. The punch member 16, however, is guided directlyin the upper guide hole 15 of the upper arm 11 of the (l2-frame, thereby eliminating any build-up in tolerance as was heretofore the case where the punch member reciprocated in the stripping member which in turn was mounted in the-C-frame. This feature is of especial importance because in heavy duty perforating implements' it is extremely diicult to maintain the upper and lower guide holes for the reception of the punch and die in coaxial alignment for perforating light gauge materials. By eliminating, one of the tolerance build-ups it is possible to obtain close punch and die clearances such as are requiredin light gauge punches, despite the massive natureof-ltheparts or components involved.l

It will be noted that the punchmember 16, plate'18,

springs 27 and 28, and stripping plate 42 operate as a unit assembly through the upper arm 11 of the vC-frame and can move in unison up and down relative thereto.

rEhe lower arm 12 of the holder 10 is providedwith a bore 50 which is coaxial with bores 15 and 47. Mounted in this bore 50 is a guide ring 52. lThis ring has a collar like portion 53 whose peripheral surface is coaxial with Vbore 50 and engages in a countersunk hole 54-of the die plate 55. The die plate 55 is adapted to be secured removably to the lower arm 12 of the holder by screws 56 that are mounted in recesses 57 in the lower arm and that thread into the plate 55. This construction insures that the plate 55 will be in coaxial alignment with the punch member 16.

A die plate S will be used at anyfone time that has' a I bore 58 shaped in accordance with the cross-sectional shape of the operating end 48 of the punch member 16, that is, in accordance with the shape of the hole which it is desired to punch in the work. ln Fig. 3, the hole 58 is shown as triangular in shape; and, of course, the working end 48 of the punch member would be correspondingly shaped.

The use oi a removable die plate 55 is a novel feature of the present invention. y Itallows the use of flat ground steel plates for dies, instead of requiring dies having latheturned downwardly-projecting anges for engaging the arm 12 of the holder. The conventional lathe-turned die may be used in the perforating implement of the present invention where a round hole is to be perforated. However, where a hole other than non-circular shape is to be punched, a plate such as shown at is employed. Such a plate can itself be punched. Hence its cost is reduced; and its production is simplified.

The punch and die must be maintained in alignment while perforating is taking place. This is a critical item when a heavy duty unit is used for light gauge punching. To achieve this alignment, a key 60 (Figs. l and 4) is used for the punch member. This key is secured to the upper arm 11 by a screw 61, and is adapted to extend into the bore 1 5 of ,the upper arm to engage selectively in one of two grooves orbite; '62, 62', in the periphery of the punch member 16, 90 apart. The key 60 serves to guide the punch member directly in the holder. A key (Figs. l and 3) is also provided on the lower arm 12 of the holder to engage simultaneously both into a keyway 66 formed in the undersurface of die plate 55 and in a registering keyway 67 formed in the upper face of the lower arm 12.

In addition, a pilot'pin 70, which projects downwardly from the under face of the arm 12, may be used when the perforating unit is utilized for punching round holes. A second pilot pin 71 is also provided to project downwardly beyond the bottom face of the arm 12. This second pilot pin is used when shaped holes are to be punched. Its purpose is to position the punch with reference to the workpiece to properly orient the punch to have the shaped holefextendii'n the desired direction in the workpiece.

As .has Abeen 'previously mentioned, the punch stripping assembly, which is denoted as a whole at 75, and which comprises the punch member 16, plate 18, springs 27 and 28, and stripper pressure plate 42, is a full oating element moving as a unit or assembly through the upper yholder arm 11. To lift this assembly and to keep it in its lifted or elevated position until such time as' it is engaged by' the ram of the press, to provide feed clearance between the punch and the die member for introduction of the workpieces therebetween, a plurality of lifting springs (Eig. 5.) are provided. These are mounted in holes 82 counterbored in the upper arm 11, and surround headed cap screws ,83, being4 interposed ,between the heads 84 of the screws 83, and the base of the counterbores 82. The capfscrews 83 extend through holes 85 in the arm 11, which communicate with the counterbores 82, and thread into the stripping pressure plate 42. The springs 80 are of a light exible. nature sucient in multiples to lift the punch assembly 75 to elevate itvfor feed clearance purposes. 4Because of the massive nature of the perforating assembly 475 a plurality ofthese springs, namely, four in the instance shown are provided around the punch and uniformly spaced therefromto provide a baianced lifting force.

To slo w down the punch and prevent its violent ejection due lto .itsgigertia from the holder in event the punch sticks due to failure of the spring, or d'uling o the punch, a pair of diametrically opposed clips (Figs. 2 and 4) are provided. The punch member 16 is provided with two ats 91 `and 9,1' on its periphery that are spaced 90 apart. The clips 90 are adapted to engage one or other of these flats .depending on the orientation of the punch. They serve to prevent the .punch assembly 75 from jumping out of place should the punch stick for any reason. The clips 90 are secured in position by screws 92 which thread intoholes 93 in the upper arm 11 of the holder. To provide access to the screws, the punch cap member 18, as is shown in Fig. 2, is of narrower width than the upper arm 11 of the holder.

lFig. 1 shows the punch member in its elevated position. When the ram R (Fig. 5) of the press descends, the whole punch assembly 75 is depressed until the plate 42 engages the workpiece W. Then on the further downward s troke of Vthe ram the 'working end 48 of the punch Vis driven through the work to perforate a hole therein and to force the slug punched out through the die hole 5 8, the hole A5,2 in the ringv 50 and out the slug ejection chute 95 formed in the lower arm 12 of the C-frarne. A Vthe `ram drives the assembly 75 downwardly to the position where stripper plate v42 engages the work, the springs 80 are partially compressed because of the downward movement of the stripper plate 42 to which the bolts 83 are secured. As the punch passes through the work the liquid springs 27 and 28 are compressed, be- Gause the stripper plate is held stationary by the work while the working portion of the punch is passing through thework.

When the movement of the ram is reversed the liquid springs 27 and 28 expand, forcing the plate 18 and with it the punch member upwardly withdrawing or strip- `Yping the punchtfrom the work ,gf`l`heV coil springs 80 are then free to expand to move the whole assembly 75 up'-v wardly to initial position to provide the clearance necessary for insertion of another workpiece between the punch and the die.

As previously stated, the liquid springs 27 and 28 employed have force adjusters 44-45 which permit of variation of the force of the springs by the displacement of the liquid therein. Access may be had to the force adjuster screws 45 through the holes in the stem portion 4.0 of the springs, the stem portions threading through plate 42. Thus, the stripping force of each spring 27, 28 can be adjusted to suit any particular configuration of punch or to compensate for the weakness in one spring as contrasted with the other, or for any other purpose vfor which a change in loading is desired. This is an irnportant feature of the invention.

In no previous form of spring stripping units could the spring load be varied. The present invention makes it possible to perforate an asymmetrical hole, such as a triangular hole, which is so located as to require a greater stripping force on the one stripping spring than o n the other. In the example shown in the drawings, a punch and die are shown shaped to punch a triangular hole in the work. The triangular hole is to be located in a workpiece in a position necessitating the positioning of the punch and the die member in such fashion, in order to enable the perforating thereof, that the major portion of the stripping force will be on the spring 28, since it is on the side where the maximum punch contact with the punched hole takes place. Accordingly, the force adjuster for spring 28 will be adjusted so that this spring will take a higher load than spring 27 so as to provide suliicient stripping forces at both sides of the punch axis. This is an achievement not heretofore attainable in any self-Contained perforating unit. It will be thus noted that by virtue of the spring construction and its application perforating of asymmetrical holes as well as symmetrical holes can be effected with the same holder assembly, thus providing great flexibility.

While the springs 27 and 28 are completely flexible with respect to loads and forces for a given size of spring, it is possible to preload the spring up to its ultimate end Jpad if desired. The one item, however, with respect to which the perforating implements cannot be adjusted by adjustment of the springs is for wear on the punch member itself. This is particularly critical in heavy duty perforating where the punch, say, is perfoiating three-quarter inch stock. This type of work causes great wear on the surface of the punch and is something that must be corrected, in order to get any substantial life out of the punch member 16. While the punch member 16 has been designed so that it is a simple piece of tool steel, and the conventional head is eliminated, eliminating the expensive machining connected therewith, nevertheless it is .desirable to provide a reasonably long Vlife for the punch member which is still a costly item. For reason the length of the working end 48 of the punch member is made suciently longer than the maximum thickness of stock which is to be perforated, to .allow for grinding back the punch member to provide a new cutting surface when the original cutting surface be- 8 comes dull. When the punch is ground back, however, its length is shortened. This creates difficulty in that the maximum length of travel of the spring member is but slightly greater than the maximum thickness of the stock to be perforated .by the punch.

To overcome this diculty, and to provide the maximum stripping force and travel for any particular length of punch, the washer members 22 are provided. These are so constructed that they may be interposed between the top face of the punch member 16 and the cap member 18 as spacers to compensate for the reduction in length of the punch due to wear. Identical washer members 22 may be fitted, as shown in Fig. 1, under the spring members 27 and 28 initially to serve as spacers there. A stock of such washers 22 maybe mounted upon the upper arm 11 of the holder by a screw 98, thereby providing a supply of such spacers for use to compensate for wear of the punch.

The 'first time that the punch is sharpened the washers 22 are removed from under the springs 27 and 28, thereby compensating for the amount of stock removed from the punch in the sharpening operation. The second time that the punch is sharpened a washer is inserted between the punch member 16 and the punch cap 18 to lengthen the punch still further. On the third sharpening, more washers are inserted between the punch member 16 and the cap member 18 to compensate for the added wear, etc.

Figs. 6, 7 and 8 show how the perforating unit of this invention may be adapted for punching holes of smaller diameter and lighter stock thickness, than that for which punch member 16 is adapted, thereby further demonstrating the universal character of this perforating implement.

In Fig. 6 the punch member is denoted at 100 and the working end of this punch member is designated 102. This punch member is a conventional headed punch similar to that conventionally used for perforating stock up to one-quarter inch thickness. In order to use this punch member in the perforating unit of the present invention it is secured in a tubular spacer or adaptor member 103 whose outside diameter is such as to fit the hole 1S in the upper arm 11 of the C-frame. A set screw 104 that threads into the tubular member '103 serves to secure the punch in the tubular member 103. This set-screw engages in an elongate slot 105 in the punch member 100. The elongate slot 105 permits of adjustment of the punch member for sharpening. Washers 22 may be inserted between the top face of the tubularmember 103 and vthe underface of the punch cap 13 to compensate for wear of the punch member in sharpening. The punch cap 18' is identical with the punch cap 18 except for the countersunk hole 107 provided therein to reecive the head 108 of the punch member. Otherwise the structure of the perforating unit of Fig. 6 is the same as previously described; and it operates as previously described.

With the present invention, therefore, it is possible to use standard headed perforating punch members 100 from another series of punches to provide for light gauge punching. It will be noted that by using the smaller size punch member 100, it is possible to eliminate any sharp transition between .the working end 102 of the punch and the body of the punch member. If the punch 16 of Fig. 1 was reduced down at its working end to provide a working end of the small size of the working end 102, there would be such sharp transition between the working end of the punch member and its body that the punch tip would break down because in heat treatment the transition point between the two masses of metal would cause strains to develop which would result ultimately in rupture of the punch.

Another modified construction is shown in Fig. 7 in which a smaller size punch or insert is used. Here the punch member 110 is again a headed punch of conventional construction and is mounted in a tubular member 113, being secured therein by a set-screw 114 which engages in the elongate slot 115 in the punch member. Here, however, the punch member tits into a socket in the tubular member and is held therein by a threaded plug 116 which threads into the bore 117 of the spacer member 113 and seats the head 118 of the punch against the shoulder 119 of that bore, causing the punch member to be tightly held in the tubular member.

The punching load is therefore transmitted from the punch member 11) through the plug 116, tubular member 113, and punch cap 18. The tubular member 113 is secured to the punch cap 18 by a screw 120 whose head is countersunk into the cap member 13. Stripping loads are carried through the cap 18the screw 120, the tubular member 113, and the shoulder 119 to the head 118 of the punch member. The construction of Fig. 7 is used where the diameter of the punching extremity 122 of the punch is smaller than that shown in Fig. 6, because if such a small diameter working end were joined to a long columnar punch body such as shown at 100 in Fig. 6, there would be again the danger of breakdown due to strains in heat treatment.

A further modification of punch unit is shown in Fig. 8. Here the punch member is denoted at 130. It is secured in a sleeve member 133 by a set screw 134 which engages in an elongate slot 135 in the punch member. In this case, however, the head 13S of the punch member is seated against the shoulder 139 formed in the bore 137 of the tubular member 133 by a special threaded bushing 140 which is threaded externally to thread into the tubular` member 133 and which is threaded internally to receive the screw 142 by which the punch member is fastened to the cap member 18. The threaded bushing 140 carries the punching load from the punch head 138 to the punch cap 18.

This form of construction is utilized where a hole of small size is to be punched in relatively thin stock, but where the loads are substantial because the metal, which is to be perforated, is a heat treated material of high strength and high shear resistance. The modification of Fig. 8 has advantage because it carries the punching load directly to the punch cap 18. It does not depend on the threaded section for this purpose. However, this construction is more costly than that of Fig. 7.

In the various embodiments of the invention illustrated, it will be obvious the stripper plate 42 can be shaped to suit the configuration of the work. Thus it might be tapered to be used with tapered sheets of structural steel, etc.

The pilot pins 70 and 71 (Fig. l) permit of locating the perforating implement in accordance with the desired location of the hole to be punched in the work. The two key ways 62, 62 and ats 91, 91 further permit orientation of the punch in accordance with the desired location of the hole to be punched.

The present invention therefore provides a perforating implement with which various types and shapes of punches and dies can be used, inwhich the stripping load can be adjusted in accordance with the thickness of material to be punched, in which the spring load can be adjusted even to secure balanced stripping where an asymmetrical hole is to be punched, in which there is sufcient stripping load for even the greatest thickness of stock and yet in which the slight stripping load desired for very thin stock is also available, and in whichthe desired stripping loads can be maintained even after the l punch is sharpened and throughout its whole life. A truly universal perforating implement is therefore provided.l

While several diierent embodiments of the invention have been illustrated, it will be understood that the invention is capable of further modification; and this application is intended to cover any variations, uses, or adaptations of the invention, following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

l. A self-contained perforating implement comprising a C-frame having an upper and a lower arm, a punch reciprocably mounted in said upper arm and having an operating portion at its lower end which is non-circular in cross section, the lower arm having a bore axially aligned with said punch, a die locating ring secured in said bore coaxial therewith, a removable die member having a bore which is non-circular in cross section and which has a cross-sectional shape corresponding to the cross-sectional shape of the operating portion of said punch, said die member being mounted above said ring and having a counterbore to receive said ring, a key engaging both said die member and said other arm to locate said die member on said other arm angularly about the axis of the rst-named bore so that the bore of said die member is in exact registry with the operating portion of said punch as regards the cross-sectional shapes of the operating portion of said punch and the bore of said die member, and means for securing said die member to said other arm, said other arm having a slug ejection chute communicating at one end with said bore.

2. A self-contained perforating implement comprising a holder, a die member secured to said holder, a punch member reciprocable on said holder in alignment with said die member, a stripper member mounted wholly outside of said holder and reciprocable relative to said holder and relative to said punch, a plurality of spaced liquid springs containing a compressible liquid secured to said stripper member and resiliently connecting said punch member and said stripper member and resiliently holding said punch member against movement relative to said stripper member, and a plurality of resilient lifting members connecting said stripping member to said holder and for lifting said stripping member, punch and liquid springs as a unit to provide feed clearance between said punch and said die member for the work.

3. A self-.contained perforating implement comprising a holder, a punch reciprocable on said holder, a stripper plate mounted wholly outside of said holder and having an opening through which said punch extends, a plurality of stripping springs mounted about the axis of said punch and resiliently connecting said punch to said stripper plate, and means accessible from one side of said implement for adjusting the load-capacity of said stripping springs while in said implement.

4. A self-contained perforating implement comprising a holder having a bore, a punch member reciprocal directly in said bore and guided thereby in its reciprocating movement, a stripper plate disposed outside said holder, and a stripping spring reciprocably mounted in said holder in oiset relation to said bore and resiliently connecting said punch and said stripper plate.

5. A self-contained perforating implement comprising a C-frame having upper and lower arms, one of said arms, having a bore therethrough, a punch member reciprocal in said bore and having an operating portion at one end, a, connecting plate secured to said punch member at its opposite end and outside of said one arm, a stripper plate disposed outside of said one arm at the opposite side thereof from said connecting plate and having a bore therethrough aligned with the first-named bore and through which the operating end of the punch member may project in a perforating operation, and a pair of springs reciprocable in said one arm at opposite sides, respectively, of said bore and resiliently interposed between and connecting said two plates.

6. A self-contained perforating implement comprising a 'C-frame having upper and lower arms, one of said arms having a bore therethrough, a punch member reciprocal in said bore and having an operating portion at one end,

ak connecting plate secured to said punch member at its opposite end and outside of said one arm, a stripper plate disposed outside of said one arm 'at the opposite side thereof from said connecting plate and having a bore therethrough aligned with the ltirst-n'amed bore and through which the operatingend of the punch member may project in a perforating operation, a pair of liquid springs reciprocal in said frame at opposite sides, respectively, of said bore and resliently interposed between and connecting said two plates, and means for separately adjusting the compressive force of each spring.

7. A self-contained per'foratin'g implement comprising a `G-frame having upper and lower arms, one of said arms having a bore therethrough, a punch member reciprocal in said bore and having an operating portion at one end, aipair of stripping springs reciprocal in s'aid one arm 'at opposite sides of said bore, a stripper plate disposed at one side of said one arm and having a bore therethrough aligned with the irst-namedbore and through which the punch member may project in a perforating operation, means disposed at the opposite side of said one arm connecting said springs to said punch member, and means connecting said springs to said stripper plate, whereby to resliently connect said punch and stripper plate for movement together, and a lifting spring connecting said stripper plate with said one arm to lift the assembly comprising punch, stripper plate and stripping springs.

8. A self-contained perforating implement comprising a `C-frame having upper and lower arms, one of said arms having a bore therethrough, a punch member reciprocable directly in said bore and guided thereby, a stripper member, resilient stripping means connecting said punch member and said stripper member and reciprocable in said one arm, and means secured to said one arm and directly engaging said punch member and preventing it from jumping out of said bore when stripped from a workpiece.

9. A self-contained perforating implement comprising a `C-frame having upper and lower arms, one` of said arms having a bore and having peripheral engagement therewith therethrough, a punch member reciprocable in said bore, said punch member having a plurality of angularlyspaced axially-extending guide slots around its periphery and having a plurality of angularly-spaced stop shoulders around its periphery and being adjustable rotatably in said bore about its axis, a stripper member, resilient stripping means connecting said punch member and said stripper member and reciprocable in said onearm, a `key member secured to said one arm and engageable selectively in one of said guide slots to guide said punch member in its reciprocating movement in any adjusted position, and a stop member secured to said one arm and engageable with one of said shoulders in ,the adjusted position of said punch member.

10. A self-contained `pertoratingimplement `comprising a C-frame having upper and lower arms, one of said arms having a bore therethrough, a4 punch member reciprocable in said bore and having an operating portion at one end, a connecting plate secured to the opposite end of said punch member, a stripper plate disposed at the opposite side of said one arm from said connecting plateand having a bore therethrough aligned axially with the firstnamed bore and through which the operating end of the punch member projects in aperforating operation, and a pair of stripping springs disposed inA said one arm at opposite sides of said tirst-named bore and reciprocabletin said one arm, each of said springs comprising acontainer, a piston reciprocable in said container, and a compressible medium filling said container, the `pistons of the tw'o springs being connected to one of said plates and the containers of the springs being connected 'to the other plate.

l1. A self-contained perforating implementcomprising `a `C-t'rame having upper and lower arms, one of said arms having a bore therethrough, a punch member reciprocable in said bore and having an operating portion at one end which is asymmetrical of said bore, a die mounted i the other arm 'inalighm'eht with said punch member and having an `ope'iring therein corresponding in shape to the shape of the operating portion of said punch member, a stripper plate, means for 'atigning said die with said operating portion ot said punch so that said opening is in exact registry with `the asymmetrical operating portion of said punch, a plurality 'of spring stripping members interposed between said punch and said stripper plate to connect said punch member and stripper plate together but to permit resliently-restrained movement between said punch inember and stripper plate, and means for separately adjusting the stripping capacity on each of said spring stripping members while in said implement to compensate for the asymmetrical forms of said punch member and die.

l2. A self-contained perforating implement comprising a C-framehaving upper and lower arms, one of said arms having 'a'bore `therethrough, a punch member reciprocable in saidbore and having an operating portion at one end, va connecting plate connected to the opposite end of said punch member and adjustable axially relative thereto to compensate for wear of the punch member in sharpening, a stripper plate disposed at the opposite side of said 'one 'arm from said connecting plate, a pair of stripping springs reciprocable in said one arm through holes disposed atvopposite sides of said bore, said springs being interposed between said two plates to connect said two plates to move together but to permit relative movement between said` plates, and said springs being adjustable in the direction ofthe a'xis of said bore to compensatie for wear of the punch member in sharpening.

`13. A self-contained perforating implement comprising a C-framehaving upper and lower arms, one of said armshaving a bore therethrough, a tubular member re- 'ciprocabie'i'n saidbore, a punch sectire'd in said tubuiar member to reciprocate therewith, a stripper member disposed wholly Joutside of said one arm, a stripping spring member disposed at -one side of said bore and reciprocable in 'said one arm and operatively connecting said stripper member and saidpuneh.

14. A self-contained perforating implement comprising a-C-frame having upper and lower arms, one of said arms'havinga bore therethrough, a tubular member reciprocable in ,said borea punch secured in said tubular member to reciprocate therewith, said punch having an `operating p'ortionat `one end and a head `at its opposite end `a.'connecting plate disposed at one side of 'said one arm to which said head is secured, a stripperplate disposed at the opposite side of said one arm from said connecting plate, and a pair of stripping spring members disposed at opposite sides of said bore and reciprocable in said one arm and resliently connecting said two plates, saidpunch being adjustable axiallyin said tubular member 'and said tubular member being adjustable axially relative to said connecting plate to compensate for wear of said punch in sharpening.

l5. A` 'self-'contained perforating implement comprising a C-frame having upper and lower arms, one of said farrrlslhavin'g aboretherethrough, a tubular member reciprocablein said bore, a punch secured in said tubular member to reciprocate therewith, said punch having an operating portion 'at one end and a head atits opposite end, 'said tubular member having an internal shoulder against which 'said head seats, a seatingmember threaded into said tubular 'member to hold said'head against said shoulder, a connecting plate disposed at one sideof said one arm to which said tubular member is secured, a stripper plate `disposi-,d at the opposite side of said one arm, and a`,p'air ofstri'pping spring members disposed at opposite sides of said bore and reciprocable in said one arm and resliently connecting said two plates, said punch being adjustable axially in said tubular member and said tubular 'member ,being adiustabley axially relative to said connecting `plate to compensate for wear of said punchin sharpening.

16. A self-containedperforating implement comprising a C-frtne having upper and lower arras, one of said arms having a bore therethrough, a tubular member reciprocable in said bore, a punch secured in said tubular member to reciprocate therewith, said punch having an operating portion at one end and a head at its opposite end, said tubular member having an internal shoulder against which said head seats, a seating member threaded into said tubular member to hold said head against said shoulder, a connecting plate disposed at one side of said one arm, a screw threaded into said seating member to secure said seating member and said tubular member to said connecting plate, a stripper plate disposed at the opposite side of said one arm, and a pair of stripping spring members disposed at opposite sides of said bore and reciprocable in saidl one arm and resiliently connecting said two plates, said punch being adjustable axially in said tubular member and said tubular member being adjustable axially relative to said connecting plate to compensate for wear of said punch in sharpening.

17. A self-contained perforating implement comprising a C-frame having upper and lower arms, one of said arms having a bore therethrough, said bore being of a diameter to receive selectively a large diameter punch member, which has an operating portion at one end and which is reciprocable directly in said bore, or a tubular adaptor which is reciprocable in said bore and which is adapted to hold and to be secured to a smaller diameter punch, a connecting plate disposed at one side of said one arm and securable tosaid large diameter punch or to said adaptor, as the case may be, a stripper plate disposed at the opposite side of said one arm, and a pair of stripping springs reciprocable in said one arm and disposed at opposite sides of said bore and interposed between and resiliently connecting said plates.

18. A self-contained perforating implement comprising a C-frame having upper and lower arms, one of said arms having a bore therethrough, a punch reciprocable in said bore and having an operating portion at one end, a die mounted in the other arm in axial alignment with said punch, a connecting plate secured to said punch, a stripper plate interposed between said one arm and said die and having a boreitherethrough axially aligned with the first-named bore and through which the operating end of said punch projects in a perforating operation, a pair of stripping springs disposed in said one arm at opposite sides of said bore and reciprocable in said one arm, each of said springs comprising a container, a piston reciprocable in said container, and a compressible medium lling said container, the pistons of said two springs being connected to one of said plates and the containers ot said springs being connected to the other plate, and resilient lifting means connecting said stripper plate to said one arm.

19. A self-contained perforating implement comprising a C-frame having upper and lower arms, one of said arms having a bore therethrough, a punch reciprocable in said bore and having an operating portion at one end, a die mounted in the other arm in axial alignment with said punch, a connecting plate secured to said punch, a stripper plate interposed between said one arm and said die and having a bore therethrough axially aligned with the firstnamed bore and through which the operating end of said punch projects in a perforating operation, a pair of stripping springs disposed in said one arm at opposite sides of said bore and reciprocable in said one arm, each of said springs comprising a container, a piston reciprocable in said container, and a compressible medium iilling said container, the pistons of said two springs being connected to one of said plates and the containers of said springs being connected to the other plate, and resilient lifting means connecting said stripper plate to said one arm, and means engaging said punch for stopping the stripping movement of said punch to prevent said punch from being ejected from said bore upon the stripping operation.

20. A self-contained perforating implement comprising a C-frame having upper and lower arms, one of said arms having a Ibore therethrough, a punch reciprocable in said bore and having an operating portion at one end, a die mounted in the other arm in axial alignment with said punch, a connecting plate secured to said punch, a stripper plate interposed between said one arm and said die and having a bore therethrough axially aligned with the Irst-named bore and through which the operating end of said punch projects in a perforating operation, a pair of stripping springs disposed in said one arm at opposite sides of said bore and reciprocable in said one arm, each of said springs comprising a container tilled with a compressible liquid and provided with a cylinder opening at its inner end into said container, a piston reciprocable in said cylinder, and means in each spring for adjusting its pre-load, the pistons of said two springs being connected to one of said plates and the containers of said springs being secured to the other plate, and resilient lifting means connecting said stripper plate to said one arm.

21. A self-contained perforating implement comprising a C-frame having upper and lower arms, one of said arms having a bore therethrough, a punch reciprocable in said bore and having an operating portion at one end, a die mounted in the other arm in axial alignment with said punch, a connecting plate secured to said punch, a stripper plate interposed between said one arm and said die and having a bore therethrough axially aligned with the first-named bore and through which the operating end of said punch projects in a perforating operation, a pair of stripping springs disposed in said one arm at opposite sides of said bore and reciprocable in said one arm, each of said springs comprising a container lled with a compressible liquid and provided with a cylinder opening at its inner end into said container, a piston reciprocable in said cylinder, and means in each spring for adjusting its pre-load, `the pistons of said two springs being connected to one of said plates and the containers of said springs being secured to the other plate, and resilient lifting means connecting said stripper plate to said one arm, and means secured to said one arm to engage said punch to prevent said punch from being ejected from said bore upon the stripping operation.

References Cited in the le of this patent UNITED STATES PATENTS 2,118,648 Johnson May 24, 1938 2,355,344 Wales Aug. 8, 1944 2,704,125 Taylor Mar. 15, 1955 

